Should I? Me and my cousin are not terribly close but she's my favorite cousin and I'm closest with her than any of my other cousins.
She's 16 and very mature for her age, she hangs out with me a lot (im 22) and my likewise aged friends because she prefers our level of humor and conversation, but she isn't without her young minded antics.
She's the most open minded cousin I have and she is constantly coming over my house and borrowing my wife's clothes from the closet (which is fine) but I keep all my diapers in the closet, you'd have to blind or a fool not to notice them. Not to mention that we've drunk texted before when I was in a dark place in my marriage about my wife disliking my abdl side, and although I didn't go into detail with my cousin, she said I could talk to her about anything.
Also id like to add that me and my wife are moving out like I previously mentioned in another post (My First Step to ABDL Freedom!) And I do plan on having her over plenty of times because like I said, she's my favorite cousin.. And I plan on being fully open with my hobby/lifestyle when I move out.